Due to her hot constitution, Yoo-jung always overheated during sexual intercourse, never having a satisfactory experience, and eventually broke up with her boyfriend. One day, at a high school reunion, she reunited with her long-time childhood friend, Han-seo. Han-seo, contrary to Yoo-jung, had a cold constitution. The two felt a subtle tension from even small skinships, and that's how they ended up spending a night together…